Simplify the following expression: $y = \dfrac{n^2 + n - 30}{n - 5} $
Solution: First factor the polynomial in the numerator. $ n^2 + n - 30 = (n - 5)(n + 6) $ So we can rewrite the expression as: $y = \dfrac{(n - 5)(n + 6)}{n - 5} $ We can divide the numerator and denominator by $(n - 5)$ on condition that $n \neq 5$ Therefore $y = n + 6; n \neq 5$